Method for volumetric printing a three-dimensional object by multi-color photopolymerization of a photocurable resin

Abstract

A method for volumetric printing a three-dimensional object by multi-color photopolymerization of a photocurable resin.

1 . A method for volumetric printing a three-dimensional object by multi-color photopolymerization of a photocurable resin, which comprises an irradiation process of irradiating, on basis of a plurality of printing parameters, a photocurable resin with light of a first wavelength and light of a second wavelength, different from the first wavelength, to form, by multi-color photopolymerization, a three-dimensional object in at least one direction,
 wherein the light of the first wavelength and the light of the second wavelength intersect in a formation zone,   wherein the method comprises spatially and/or temporally varying at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin, during the irradiation process.   
     
     
         2 . The method of  claim 1 , wherein spatially and/or temporally varying at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin, comprises that the photocurable resin is irradiated with the light of the first wavelength before it is irradiated with the light of the second wavelength, wherein irradiating the photocurable resin with the light of the first wavelength particularly starts at a position p 1  and wherein irradiating the photocurable resin with the light of the second wavelength starts at a position p 2 , wherein p 2  is behind p 1  in the formation direction; and/or wherein irradiating the photocurable resin with the light of the first wavelength particularly starts at a time t 1  and wherein irradiating the photocurable resin with the light of the second wavelength starts at a time t 2 , wherein t 2 >t 1 . 
     
     
         3 . The method of  claim 1 , wherein spatially and/or temporally varying at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin, comprises that the photocurable resin is irradiated with the light of the first wavelength after it is irradiated with the light of the second wavelength, wherein irradiating the photocurable resin with the light of the second wavelength particularly ends at a position p 3  and wherein irradiating the photocurable resin with the light of the first wavelength ends at a position p 4 , wherein p 4  is behind p 3  in the formation direction, and/or wherein irradiating the photocurable resin with the light of the second wavelength particularly ends at a time t 3  and wherein irradiating the photocurable resin with the light of the first wavelength ends at a time t 4 , wherein t 4 >t 3 . 
     
     
         4 . The method of  claim 1  wherein spatially and/or temporally varying at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin, comprises that the photocurable resin is irradiated with the light of the first wavelength in a volume separate, particularly adjacent, more particularly directly adjacent, to the volume in which the three-dimensional object is to be printed, particularly wherein the volume is before and/or behind the volume in which the three-dimensional object is to be printed with respect to the at least one direction of the three-dimensional object. 
     
     
         5 . The method of  claim 1 , wherein spatially and/or temporally varying at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin, comprises irradiating the photocurable resin with the light of the first wavelength and/or the second wavelength and spatially and/or temporally varying the energy or the energy intensity of the light of the first wavelength and/or the second wavelength along the at least one direction. 
     
     
         6 . The method of  claim 5 , wherein spatially and/or temporally varying the energy of the first wavelength comprises that the energy of the light of the first wavelength is varied from a first energy level to at least a second energy level, the at least one second energy level being smaller than the first energy level; and/or wherein spatially and/or temporally varying the energy of the first wavelength comprises that the energy of the light of the first wavelength is varied from a first energy level to at least a second energy level, the at least one second energy level being higher than the first energy level, wherein the photocurable resin is particularly irradiated with the light of the first wavelength at the first energy level in an initial volume of the to be printed three-dimensional object which comprises at most 5%, particularly at most 3%, more particularly at most 1%, of the spatial extension of the three-dimensional object to be printed in the at least one direction, and/or wherein the photocurable resin is irradiated with the light of the first wavelength at the first energy level for an initial time of at most 10 seconds, particularly at most 5 seconds, more particularly at most 1 second, even more particularly at most 0.1 second, most particularly at most 0.01 second. 
     
     
         7 . The method of  claim 5 , wherein spatially and/or temporally varying the energy of the second wavelength comprises varying the energy or energy distribution of at least a part, e.g. a pixel, of at least one image corresponding to a cross-sectional geometry of a three-dimensional object to be printed or of at least one point or line of at least one light beam corresponding to a cross-sectional geometry of a three-dimensional object to be printed, wherein spatially and/or temporally varying the energy of the second wavelength particularly comprises varying the energy of at least a part of the image, particularly at least one pixel of the image, in a sequence comprising at least three energy levels E 1 , E 2 , and E 3 , wherein the energy level is changed from E 1  to E 2  and E 2 >E 1  and wherein the energy level is changed from E 2  to E 3  and E 2 >E 3  and particularly E 3 >E 1 . 
     
     
         8 . The method of  claim 1 , any wherein spatially and/or temporally varying at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin, comprises varying a focus parameter of the light of the first wavelength and/or varying an image parameter of an image or at least one image element, e.g. a pixel, of an image projected with the light of the second wavelength. 
     
     
         9 . The method of  claim 1 , any wherein spatially and/or temporally varying at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin, comprises irradiating the photocurable resin with the light of the first wavelength and/or the light of the second wavelength while the at least one formation zone is not moved relative to the container during the irradiation process or while the at least one formation zone is moved at a motion rate which is lower than the nominal motion rate. 
     
     
         10 . The method of  claim 1 , wherein the irradiation process comprises irradiating the photocurable resin with the light of the first wavelength and the light of the second wavelength to form a pre-polymerized three-dimensional pre-object in a first irradiation step, and wherein the pre-polymerized three-dimensional pre-object is irradiated with the light of the first wavelength and the second wavelength in a further irradiation step which causes formation of the three-dimensional object, particularly after completion of the first irradiation step and/or after completion of the at least one further irradiation step, more particularly after completion of a first further irradiation step of a plurality of further irradiation steps, wherein the photocurable resin is particularly irradiated with the light of the first wavelength and the second wavelength to form a pre-polymerized three-dimensional pre-object in a first irradiation step, wherein the pre-polymerized three-dimensional pre-object is irradiated with the light of the first wavelength and the second wavelength which causes further polymerization of the pre-polymerized three-dimensional object in a second irradiation step, and wherein the second irradiation step can be repeated multiple times. 
     
     
         11 . The method of  claim 1 , wherein the photocurable resin is irradiated with the light of the first wavelength resulting in a pre-polymerized photocurable resin in a first irradiation step, and wherein the pre-polymerized photocurable resin is irradiated with the light of the first wavelength and the second wavelength in a further irradiation step which causes formation of the three-dimensional object, particularly after completion of the first irradiation step and/or after completion of the at least one further irradiation step, more particularly after completion of a first further irradiation step of a plurality of further irradiation steps. 
     
     
         12 . The method of  claim 1 , wherein spatially and/or temporally varying at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin comprises irradiating the photocurable resin while the at least one formation zone is moved along two different directions. 
     
     
         13 . The method of  claim 12 , wherein the at least one formation zone is moved along a first motion path in a first motion direction while it is irradiated with the light of the first and/or the second wavelength, particularly while it is irradiated only with the light of the first wavelength, and wherein the at least one formation zone is moved along a second motion path in a second motion direction, particularly opposite the first direction, while it is irradiated with the light of the first and/or the second wavelength, particularly while it is irradiated with the light of both the first and second wavelength, wherein the first motion path is particularly different, particularly in length, from the second motion path, particularly wherein the first motion path is shorter than the second motion path. 
     
     
         14 . The method of  claim 1 , wherein the formation time of the three-dimensional object is at most 1 min per 1 mm extension of the three-dimensional object in the at least one direction. 
     
     
         15 . The method of  claim 1 , wherein irradiating the photocurable resin with the light of the first wavelength causes one or more photoinitiator molecules of the photocurable resin to transfer from an initial state into an intermediate state with changed optical properties compared to the initial state, such that the molecules of the one or more photoinitiators in the intermediate state can absorb the light of the second wavelength which results in that the molecules of the one or more photoinitiators are transferred from the intermediate state to a reactive state by absorption of light of the second wavelength which locally triggers the polymerization of the photocurable resin to form at least one three-dimensional object. 
     
     
         16 . An apparatus for volumetric printing a three-dimensional object by multi-color photopolymerization of a photocurable resin, which comprises an irradiation device for performing an irradiation process of irradiating, on basis of a plurality of printing parameters, a photocurable resin with light of a first wavelength and light of a second wavelength, different from the first wavelength to form, by multi-color photopolymerization, a three-dimensional object in at least one direction, wherein the light of the first wavelength and the light of the second wavelength intersect in a formation zone, wherein the apparatus comprises a controller configured to spatially and/or temporally vary at least one printing parameter, particularly a printing parameter influencing the curing behavior of the photocurable resin, during the irradiation process.